NATIONAL FEATURES OF THE RADIO FREQUENCY FIELD OF UKRAINIAN RAILWAYS AND EMC REQUIREMENTS FOR THE DESIGN OF SIGNALLING AND INTERLOCKING SYSTEMS

Abstract

Abstract

An engineering assessment is conducted to evaluate the correspondence between the radio-frequency immunity levels specified by EN 50121-4 and the actual electromagnetic environment of Ukrainian railways. This assessment covers the railway VHF band at 150–156 MHz, including portable, mobile, and stationary transmitters, as well as the 27 MHz CB band (Citizens Band) as a scenario in which radiated electromagnetic fields can induce common-mode conducted disturbances on signalling and interlocking (SCI) cables and equipment ports. The analysis demonstrates that documentary-confirmed transmitter power levels currently authorized for use in Ukraine can generate calculated field strengths exceeding the basic immunity test level of 10 V/m at characteristic distances. For the 27 MHz band, the assessment emphasizes the analysis not only of radiated fields but also of common-mode conductive interference induced on cable ports through the mechanisms of antenna coupling and grounding path impedance. The frequency-dependent immunity levels established in EN 50121-4 are examined as methodological precedents for scenario-oriented national adaptation. A three-level approach is proposed: (1) a National Annex should identify characteristic electromagnetic influences and test scenarios specific to Ukrainian railway infrastructure; (2) sectoral EMC design rules should establish zoning principles, separation distances, cable routing, shielding, bonding, grounding, port protection and verification procedures with consideration of functional safety; and (3) operational regulations should impose restrictions on personal RF transmitters used in proximity to open apparatus and require periodic verification of passive shielding measures with regard to functional safety and signal integrity throughout the equipment lifecycle.